1. Field of the Invention
The invention is directed to an apparatus for use in a subterranean well to prevent transmission of thermal expansion and contraction characteristics of a tubular conduit to an electric submersible pump which is anchored in the well by a packer, and to a completion method incorporating same.
2. Brief Description of the Prior Art
In many subterranean wells, natural production zone pressure is insufficient to lift the production fluids from the production zone through the well into the top of the well. Accordingly, artificial lift procedures must be incorporated in such wells. One of the more popular artificial life procedures incorporates the utilization of an electric submersible pump which is actuated by electric current carried to the motor of the pump through a small electric conduit into the well. When such pump is positioned on production conduit, it is normally anchored into the well by means of a packer assembly. Such packer assembly will isolate the production zone below with a zone or portion of the well thereabove. In such instances in which the production conduit is anchored within the well packer, it is possible that thermal expansion or contraction of the conduit, such as by heat due to the increased depth of the well, may be a cause of expansion of the production conduit which will, in turn, have a tendency to place component parts of the electric submersible pump and/or motor into tension or compression, thus wearing out bearings, shafts, and the like, and applying stress characteristics to the pump and reducing its efficiency and life.
The present invention is directed to a method and apparatus which addresses the problems set forth above and incorporates thermal expansion means for remedying this problem.
Additionally, the present invention also includes such thermal expansion means in a completion apparatus and method for production of the well in which a value head below the packer is selectively movable by the conduit in communication with the production conduit.